Tamper-proof closure for a pressurized container

ABSTRACT

A tamper-proof closure having an area of least strength some distance down its neck is provided. The combination of the tamper-proof closure which also has an anchor portion and a bottle which has an internal lock shoulder is part of the invention. The bottom of the anchor is indented with a recess so that the pressure coming upward in the bottle neck presses the sides of the closure against the sides of the bottle to form a better seal between the closure and the bottle. The inner side of the closure recess and the inner edge of the external lock shoulder form an area of least strength so that when pressure is applied to lift the closure out of the bottle neck, the closure snaps along the area of least strength.

Adomaitis TAMPER-PROOF CLOSURE FOR A PRESSURIZED CONTAINER DomasAdomaitis, Chicago, Ill.

Assignee: Continental Can Company, Inc.,

New York, NY.

Filed: Sept. 29, 1971 Appl. No.: 184,886

Inventor:

[4 1 Mar. 19, 1974 1.087.474 2/1955 France 215/47 PrimaryExaminerWilliam T. Dixson, Jr.

Assistant Examiner-Stephen Marcus Attorney, Agent, or Firm-AmericusMitchell; Joseph E. Kerwin; William A. Dittmann [5 7 ABSTRACT 52 US.(:1. 215/42 215/47 A tampewmf having area east [51] Int. Cl z B65d 41/20strength some distance down its neck is provided. The [58] Field of rj'l47 48 combination of the tamper-proof closure which also I. has ananchor portion and a bottle which has an internal lock shoulder is partof the invention. The bottom [56] References Cited of the anchor isindented with a recess so that the pressure coming upward in the bottleneck presses the UNITED STATES PATENTS sides of the closure against thesides of the bottle to v 3,4l l Raus ng et al. form a better sealbetween the closure and the bottle 3 2 13 3 10/1927 kausfng 215/47 Theinner side of the closure recess and the inner edge 3,345,242 iiusmg etal. of the external lock shoulder form an area of least l3 4/1935 j;215/47 strength so that when pressure is applied to lift the l:9l2:O845/1933 MarcurnI:II::::::.....,........:::::: 215/47 clsure the bottleneck the Closure Snaps almg the area of least stren th. FOREIGN PATENTSOR APPLICATIONS g 644,177 5/1964 Belgium 215/47 12 Claims, 2 DrawingFigures 9 F x 8 l x /'V I t 12 y 5 1 I 1' E l 1' l 1 1 3 1 j :1 1 1 Myinvention relates to a tamper-proof closure and particularly to atamper-proof closure having an area of less strength and shaped so thatpressure inside the container tends to seal the closure in thecontainer.

Closure means are known which have self-sealing features and in which aweakening line is featured so that the parts of the closure meansseparate along the weakening line. These closure means are particularlyused in tear-off caps.

Further features of the invention will be apparent from the followingembodiments described with reference to the accompanying drawings, inwhich:

FIG. 1 is a cross-sectional view of the tamper-proof closure of myinvention.

FIG. 2 is a cross-sectional view of the tip of a novel reamer withretractable cutting blades used to ream a lock shoulder of the neck of acontainer.

My tamper-proof closure 1 of FIG. 1 shows a sort of stopper having ananchor element 2 and an easy opening tab 3. The flexural modulus ofclosure must be lower than the flexural modulus of the bottle neck.

The material of my closure is plastic and a criterion for good operationof this device is that the flexural modulus of the material of theclosure must be lesser than the flexural modulus of the material of thebottle 4and bottle neck 5, This assures that plastic creep of theclosure will be sufficient to cause good contact between the closure andthe inner surface of the elongated neck as shown in FIG. 1. A lidelement 6 or lid portion of the closure lies above the bottle neck andis in close contact with the upper edge of the bottle neck all aroundits periphery. An easy opening tab 3 is attached to the periphery 7 ofthe lid portion and hangs downwardly somewhere in the neighborhood ofthe neck to avoid being in the way during handling.

Integral with the lid portion is .the tubular plug portion 8 having theshape generally shown in FIG. 1. This tubular portion extends a distancealong the inner surface 9 of the elongated neck to the internal lockshoulder 10 formed along the inner surface 9 of the elongated neck 5.The tubular plug portion 8 is of a size to fit snugly within the innersurface of the elongated neck. Attached at the end of the tubularportion 8 is anchor element 2.

The anchor element 2 comprises an external lock shoulder 11 whichcompliments the internal lock shoulder 10 of the bottle neck. Extendingdownwardly from the periphery of the external lock shoulder is acircular flange surface 12 which tapers inwardly as it extendsdownwardly while in the neck. The circular flange surface may be formedas an annular ring tapering in use only. The circular flange surface isin close contact with the reamed out portion of the elongated bottleneck 5. lndented into the lower portion or lower surface of thetamper-proof closure is a recess 13 having the shape of a cone, forexample. When the tamper-proof closure has been pressed into the bottleneck and falls into position as shown in FIG. 1, pressure exerted frominside the bottle will press the outer surface 14 of the tubular plugand the outer surface 12 of the anchor against inner surface 9 of thebottle neck.

The operation of the combination of the tamperproof closure 1 and thebottle retaining shoulder 10 or internal lock shoulder located in theneck 5 of the bottle is as follows. When the tamper-proof closure ispressed into the bottle neck, pressure which is applied inside of thecone recess 13 presses laterally against the anchor element 2 andagainst the conical inside 13 of the tubular plug portion 8. Thetamper-proof closure 1 is made up of plastic material having theproperty of creep. The tamper-proof closure 1 moves laterally into asnug fit against the inside of the neck. This pressure applied throughthe plastic material to the inside of the neck tends to seal the surfaceof the closure more tightly against the inner surface of the neck.Similarly, lateral pressure against the inner surface of the anchorelement operates in this fashion.

The relative length of the vectors H and V illustrates the relativevalue of the horizontal forces and vertical forces acting on theinterior surface of the closure. In the configuration of the closureshown in FIG. 1, the lateral force is several times the vertical force.The anchor and the tubular plug are forced laterally into closeengagement with the neck of the container. The anchor is forcedlaterally under the shoulder 10 which may be cut into the neck 5. Theexternal anchor shoulder 11 has an inner edge 31 located at the junctureof outer surface 14 and the external lock shoulder. The lateral force ofthe pressure inside the container insures a sealing tight fit of theclosure in the neck.

The recess is shown as extending well up into the plug portion to give ahigh horizontal force to vertical force ratio along the length of theclosure. Since it is essential that the external shoulder 11 hold fastinto the internal lock shoulder 10, the flange 12 is made several timesas long as the shoulder width and has a relatively sharp edge. The edgepresses tightly against the sloping interior neck surface under theshoulder 10. This tight fit keeps gas from getting in behind the flangesurface 12 to prevent the internal pressure of the container fromassuring a tight fit of the anchor shoulder 11 under the internalshoulder 10. The anchor must be made of a resilient material. The use ofa resilient material such as plastic tends to provide a mechanicalrigidity which holds the external shoulder 11 from turning inwardly. Italso tends to hold the edge of the flange 12 against the inwardlysloping surface of the neck.

The recess may be the shape of an inverted bowl with the flat top alongthe area of least strength of the closure shown by dotted line 15 toform a sort of truncated cone. In this configuration, lateral force isapplied to the anchor with no specific lateral force applied to thetubular plug portion.

In any configuration, the lateral area of the recess which is exposed tothe horizontal pressure inside the container should be greater than thearea taken at Horizontal pressure causes the outer wall of the closureto seal against the inner wall of the bottle neck.

At some point, it will be desired to open the bottle. In order toaccomplish this, the easy opening tab 3 is lifted and the lid is urgedupward. Since the area of least strength along line 15 has the leastplastic material cross-section, this area will be the first to snap orbreak.

When the closure breaks somewhere along the area of least strength 15,the tubular plug portion 8 becomes an ordinary stopper which can belifted out or inserted at will. Liquid flowing out through the neck ofthe bottle flows through anchor element 2 which acts as a funnel ofsorts. The conventional stopper provided by the tubular plug portion hasthe self-sealing features of the tamper-proof closure discussed above inthat the pressure acting'inside the cone recess 13 tends to press thestopper laterally against the inner surface of the bottle neck. Theanchor element 2 is wedged in place in the tapered recess formed insidethe bottle neck.

The advantages of this area of least strength configuration are: Thatthe weakest area allows an easy disconnect to form a typical stopperwhen it is disconnected. The shape of the annular element and theposition of the area of least strength allows the anchor to be insertedpast the bottle neck to the internal shoulder with a minimum ofbuckling. The closure is easily molded because the contours arerelatively smooth and there are no notches or score lines to be made inthe surface of the closure.

If the bottle is made of a plastic material and the shoulder is notmolded into the bottle neck, it is necessary to ream out the shoulder inthe bottle neck. A reaming tool 16 such as that shown in FIG. 2 is used.The reaming tool has a shoulder 18 located a certain distance up fromthe tip 19 of the reamer. If the reduced reamer shank 17 is insertedinto the bottle neck 5, the reamer stops its penetration when theshoulder 18 comes to rest against the top 20 of the neck of the bottle.After the reamer has been inserted a given distance and is turning, thenblades 21 are forced outwardly as the activating rod 22 descends betweenthem and pushes them out into the inner surface 23 of the plastic neck.Reamer 16 turns in the neck and reams material from the inner surface 23of the neck. An internal lock shoulder 24 is formed. When the blades 21have been pushed outwardly from the reamer by a given amount, then theactivating rod 22 is lifted upward and the blades 21 are pulled inwardlyby retracting spring 25. The reamer can be lifted out of the neck atthis time. The blades swing a limited angular distance about pivot pins26 located at the lower extremity 27 of each blade so that the volumecut away in the neck may be of a limited amount which does not weakenthe entire wall of the neck to the point that it will not prevent thetubular plug portion from popping out under normal usage.

The advantages of my invention are that a plastic closure is sealed in aplastic neck of a container. A good closure fit is assured and a deviceis shown for reaming out the neck in appropriate fashion. Blow-out ofthe closure in storage is minimized also and pull-out of the externallock shoulder 11 upon applying leverage to sever the cap is minimized.The area of least strength is formed in the plane of the retainingshoulder by the convergence of the barrel and the recess cone in theplane of the area of least strength for ease of moulding. The innerrounded surface of the neck under the internal shoulder is tapered andhas the effect of preventing the anchor from falling into the contentsof the container when the area of least strength is severed.

The foregoing is a description of an illustrative embodiment of theinvention, and it is applicants intention in the appended claims tocover all forms which fall within the scope of the invention.

What is claimed is:

l. In combination with a container having a neck which has an innersurface with an internal lock shoulder part way down said inner surfaceand a sloping annular surface extending downwardly from the periphery ofsaid internal lock shoulder, a tamper-proof closure comprising:

a lid engaging the top of said neck;

a plug portion extending from said lid, said plug portion having anexternal lock shoulder extending radially from an inner edge formed bythe juncture of the lower part of said plug portion and the externallock shoulder;

a generally cylindrical flange surface depending from the outercircumference of said external lock shoulder contiguous with the slopingannular surface of the neck to form an anchor element; and

a recess indented into the bottom of the tamperproof closure up to atleast the height of the external lock shoulder to form an area of leaststrength at the closest proximity of the surface of said recess and theinner edge of said external lock shoulder, whereby when said lid islifted, said tamper-proof closure breaks along said area of leaststrength and said plug portion is separated from said anchor element.

2. The combination of a container with a tamperproof closure as definedin claim 1 in which,

said plug portion is tubular whereby said plug acts as a conventionalstopper when said anchor element is disconnected from the rest of saidtamper-proof closure.

3. The combination of a container with a tamperproof closure as definedin claim 2 in which,

said plug portion is longer than said anchor element.

4. The combination of a container with a tamperproof closure as definedin claim 1 in which,

said lid extends beyond the outer perimeter of said elongated neck.

5. The combination of a container with a tamperproof closure as definedin claim 1 in which,

said recess extends inwardly beyond the area of least strength.

6. The combination of a container with a tamperproof closure as definedin claim 1 in which,

said closure is made of a material having a flexural modulus less thanthe flexural modulus of the material of the container.

7. The combination of a container with a tamperproof closure as definedin claim 6 in which,

said tamper-proof closure is made of a plastic material having theproperty of plastic creep whereby pressure which is internal of saidbottle is transmitted into the recess and presses the lateral surfacesof the tamper-proof closure against the inner surface of said neck togive a greater sealing area.

8. The combination of a container with a tamperproof closure as definedin claim 7 in which the lateral area of the recess inside the closure isgreater than the area of said recess at thereto.

9. The combination of a container with a tamperproof closure as definedin claim 1 comprising further:

a sharp edge at the juncture of the surface of the recess and thesurface of the cylindrical flange. 10. The combination of a containerwith a tamperproof closure as defined in claim 1 having the furtherlimitation that:

the vertical length of said cylindrical flange is several times theradial width of said external lock shoulder.

11. The combination of a container with a tampera lock shoulder havingan inner edge and extending proof closure as defined in claim 1comprising further: 1 adiall from the lower part of said plug;

a generally circular flange surface depending from said lock shoulderand extending away from said lid; and I a recess indented into thebottom of said tamperproof closure and extending upwardly at least to atab attached to said lid and lying close to the surface of saidcontainer whereby if said tab is lifted 5 said tamper-proof closuretends to break along said area of least strength.

12. A tamper-pro0f closure for use with a container having a neck withan internal lock shoulder compristhe level of Sam 10c]? Shoulder tofor,m an area of mg: 10 least strength at the inner edge of said lockshoula lid having a diameter greater than the neck of the whereby whenSaid lid is lifted Said p cont in proof closure breaks along said areaof least a plug portion depending from the center of said lid; strength.

1. In combination with a container having a neck which has an inner surface with an internal lock shoulder part way down said inner surface and a sloping annular surface extending downwardly from the periphery of said internal lock shoulder, a tamper-proof closure comprising: a lid engaging the top of said neck; a plug portion extending from said lid, said plug portion hAving an external lock shoulder extending radially from an inner edge formed by the juncture of the lower part of said plug portion and the external lock shoulder; a generally cylindrical flange surface depending from the outer circumference of said external lock shoulder contiguous with the sloping annular surface of the neck to form an anchor element; and a recess indented into the bottom of the tamper-proof closure up to at least the height of the external lock shoulder to form an area of least strength at the closest proximity of the surface of said recess and the inner edge of said external lock shoulder, whereby when said lid is lifted, said tamper-proof closure breaks along said area of least strength and said plug portion is separated from said anchor element.
 2. The combination of a container with a tamper-proof closure as defined in claim 1 in which, said plug portion is tubular whereby said plug acts as a conventional stopper when said anchor element is disconnected from the rest of said tamper-proof closure.
 3. The combination of a container with a tamper-proof closure as defined in claim 2 in which, said plug portion is longer than said anchor element.
 4. The combination of a container with a tamper-proof closure as defined in claim 1 in which, said lid extends beyond the outer perimeter of said elongated neck.
 5. The combination of a container with a tamper-proof closure as defined in claim 1 in which, said recess extends inwardly beyond the area of least strength.
 6. The combination of a container with a tamper-proof closure as defined in claim 1 in which, said closure is made of a material having a flexural modulus less than the flexural modulus of the material of the container.
 7. The combination of a container with a tamper-proof closure as defined in claim 6 in which, said tamper-proof closure is made of a plastic material having the property of plastic creep whereby pressure which is internal of said bottle is transmitted into the recess and presses the lateral surfaces of the tamper-proof closure against the inner surface of said neck to give a greater sealing area.
 8. The combination of a container with a tamper-proof closure as defined in claim 7 in which the lateral area of the recess inside the closure is greater than the area of said recess at 90* thereto.
 9. The combination of a container with a tamper-proof closure as defined in claim 1 comprising further: a sharp edge at the juncture of the surface of the recess and the surface of the cylindrical flange.
 10. The combination of a container with a tamper-proof closure as defined in claim 1 having the further limitation that: the vertical length of said cylindrical flange is several times the radial width of said external lock shoulder.
 11. The combination of a container with a tamper-proof closure as defined in claim 1 comprising further: a tab attached to said lid and lying close to the surface of said container whereby if said tab is lifted said tamper-proof closure tends to break along said area of least strength.
 12. A tamper-proof closure for use with a container having a neck with an internal lock shoulder comprising: a lid having a diameter greater than the neck of the container; a plug portion depending from the center of said lid; a lock shoulder having an inner edge and extending radially from the lower part of said plug; a generally circular flange surface depending from said lock shoulder and extending away from said lid; and a recess indented into the bottom of said tamper-proof closure and extending upwardly at least to the level of said lock shoulder to form an area of least strength at the inner edge of said lock shoulder, whereby when said lid is lifted said tamper-proof closure breaks along said area of least strength. 